Standard GSM networks and networks derived from them are not designed for a plurality of users to use the same user terminal. Users personalize the terminals they use by inserting in the terminals a subscriber identification module (SIM) card containing an international mobile subscriber identity (IMSI) which determines the account to which calls will be billed. After an initialization phase, this terminal is designated in radio messages by a temporary mobile subscriber identity (TMSI) which protects the anonymity of the user. An authentication procedure uses a secret key stored in the SIM card to prevent fraudulent use of the IMSI or the TMSI of another user when a call is sent and when a call is received.
The use of a plurality of fixed radiotelephone terminals to connect the same switch to a GSM network raises the problem of coordinating the terminals because a plurality of available terminals must be prevented from responding at the same time to a seek message concerning the same user terminal.
Document GB 2 293 524 describes a process for solving these problems but does not describe means for coordinating and optimizing the use of a plurality of fixed radiotelephone terminals used under such conditions.